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February 16, 2011

Challenging 'behavioral modernity'

This issue of behavioral modernity is something I have never really accepted from mainstream Prehistory and Anthropology. In this conceptual paradigm or intellectual fetish (whatever you prefer to call it), humankind almost suddenly emerged from the amorphous shadows of what we could call (by contrast) behavioral primitivism and began being us, maybe when they decided to create some perdurable art like that we can find in the caves of Southwestern Europe and the related technologies defined as mode four (or blade-based stone industries or Upper Paleolithic in the narrowest possible sense).

The reference is silly and eurocentric but very real in these academic fields. As of late, the finding of other, more ancient and not really European expressions of prehistoric artwork, notably in Palestine, North Africa and South Africa (in this chronological order per the available data) allowed the concept to escape its original sin of Eurocentrism somewhat but, regardless, is the concept real?

A new study by John J. Shea, published in Current Anthropology (pay per view, discussed at Science Daily), challenges this, already quite shattered perception of some almost miraculous transition towards behavioral modernity on scientific grounds: Shea analyzes the rather well documented early Humankind in East Africa between 250,000 and 6000 years ago, and finds no linear pattern of evolution but rather an outstanding array of nonlinear diversity.

From the news article:

A systematic comparison of variability in stone tool making strategies over the last quarter-million years shows no single behavioral revolution in our species' evolutionary history. Instead, the evidence shows wide variability in Homo sapiens toolmaking strategies from the earliest times onwards. Particular changes in stone tool technology can be explained in terms of the varying costs and benefits of different toolmaking strategies, such as greater needs for cutting edge or more efficiently-transportable and functionally-versatile tools. One does not need to invoke a "human revolution" to account for these changes, they are explicable in terms of well-understood principles of behavioral ecology.

33 comments:

Whether AMH developed novel behaviours 25kybp or 250kybp is less interesting than the question of just which traits allowed AMH to almost completely replace all of the other Homo sp that had been successfully established in Eurasia for more than a megayear.

Diamond has said that "Guns, Germs, and Steel" let Europeans overrun the Americas. (Although, IMO, it was the germs that were decisive.) But I think it unlikely that AMH brought new diseases OOA, as Eurasia would never have been out of contact with African diseases.

One tantalizing clue is that there is no evidence that other Homo sp caused mass extinctions with their range expansions. Other Homo seem to have functioned as classic top omnivores, similar to brown bears, eating opportunistically, but without great environmental impact. Numbers likely limited by intraspecies competition.

In contrast AMH has caused mass extinctions everywhere we have gone. Pleistocene sp that survived many interglacial periods under predation from other Homo sp vanished very rapidly when AMH showed up. Perhaps the critical modern behaviour of AMH (not shared with any other Homo sp) is the ability to organize into larger social groups - with devastating results for other species?

Perhaps the critical modern behaviour of AMH (not shared with any other Homo sp) is the ability to organize into larger social groups - with devastating results for other species?

Perhaps not organization per se, but the ability to look past superficial differences, moderate youth behavior for better survival (in part via longevity of elders), and the acceptance of concepts like trust, trade, and communication via a common language - all would benefit the greater good, help constructive competition, and prevent inbreeding.

I think stone tools are an absurd measure of that, and the investigators of course find the obvious: until more recent times, stone tools don't tell you much.

Other items (traded objects like beads, traveling distance of shells and rocks, art, music, patterns of sustenance, etc.) tell you much more - just indirectly, and require insight and intuition for interpretation.

"Whether AMH developed novel behaviours 25kybp or 250kybp is less interesting than the question of just which traits allowed AMH to almost completely replace all of the other Homo sp that had been successfully established in Eurasia for more than a megayear".

Maybe but that's another debate, IMO. "Behavioral modernity" is not even debated in terms of species because the very concept implies (at least in the mainstream model) that H. sapiens was already around before this "behavioral modernity". Or in the alternative "Neanderthalist" viewpoint shared between both big brained species.

It's something that allegedly happened to the genus Homo or part of it. The neanderthal-sapiens dichotomy is less important here (though not totally unimportant) in part because the concept was built when both species were considered to be just one, at least often enough to create confusion on where the biological boundary is, if anywhere.

"Diamond has said"...

Just a populist history author. Anyhow, I do not think it's comparable with the conditions of Paleolithic.

I'm getting the impression sometimes that some people in North America and Australasia, so impressed by their own recent history (of guns and steel, I doubt germs are so important), need to extrapolate to other periods of the past without even considering the dramatic differences between them, notably the brutal capability, often ignored, to move millions and millions across vast distances in a semi-organized manner.

Modern history, industrialization, has no precedent, so let's not fantasize that it happened in the Paleolithic too. We are much better looking at how modern hunter-gatherers live and understanding how different dynamics in such societies are.

This is not just important in order to understand prehistory and even history but also to understand what makes us humans and why nothing has been ok since the Metal Ages. The ages' myth is not just a myth: it tells in simple terms how humankind decayed in freedom and happiness (and hence in wisdom) while improving in technology and social hierarchization.

"In contrast AMH has caused mass extinctions everywhere we have gone. Pleistocene sp that survived many interglacial periods under predation from other Homo sp vanished very rapidly when AMH showed up. Perhaps the critical modern behaviour of AMH (not shared with any other Homo sp) is the ability to organize into larger social groups - with devastating results for other species?"

I completely agree with everything in that paragraph. I'm sure it was the 'ability to organize into larger social groups' that allowed more 'efficient' hunting. Pre-AMHs probably lived in just small family groups, so hunting was a more hit or miss affair.

"Other items (traded objects like beads, traveling distance of shells and rocks, art, music, patterns of sustenance, etc.) tell you much more - just indirectly, and require insight and intuition for interpretation".

And are indicators of the development of wider social connections.

"the very concept implies (at least in the mainstream model) that H. sapiens was already around before this 'behavioral modernity'".

Very true.

"In this conceptual paradigm or intellectual fetish (whatever you prefer to call it), humankind almost suddenly emerged from the amorphous shadows of what we could call (by contrast) behavioral primitivism and began being us"

And I'm sure it was the early attempts to make the haplogroup evidence coincide with the sudden appearance of 'behavioural modernity' that has led to the huge differences in the proposed dating for any OoA.

"the 'ability to organize into larger social groups' that allowed more 'efficient' hunting".

I have not the slightest idea of what are you talking about. Do you think Bushmen or Hadza or Nganasan or Fueguinos, for example, fit in that description? I do not think so and I think it is most difficult to find such "larger social groups" for alleged more intensive hunt.

Regardless, they may have co-factored in extinctions, as ecosystems are always dynamic and we are not detached from them but I think you exaggerate the destructive nature of our species, specially before the Neolithic.

"Pre-AMHs probably lived in just small family groups"...

The only "pre-AMH" reference we have are chimpanzee and bonobos and none of them live in "small family groups" but in larger communities. All living "primitive" H. sapiens do as well, except to some extent in the marginal habitat that is the Arctic, where resources are much more scarce and scattered.

"And I'm sure it was the early attempts to make the haplogroup evidence coincide with the sudden appearance of 'behavioural modernity' that has led to the huge differences in the proposed dating for any OoA".

You are probably right to at least some extent here. It was surely a factor indeed.

Agree with most of comments above. However do not agree with the idea that life was happier or more free before the metal ages.

My locality (Aotearoa/New Zealand) was (barely) neolithic (some agriculture) until the late 18th century. The pre-metal age culture had a surprisingly high degree of social stratification - little of which would have been evident in archeological remains. Warfare, slavery, and cannibalism were constant. The lives of most non-elite people, were short and filled with misery and terror. Most women had a very low status. I suspect that pre-metal age life was more often like this than the idyllic times we imagine.

But they were Neolithic: Austronesian culture has deep Neolithic roots that cannot be ignored (even if in some spots they may have "regressed" somewhat).

They should never be used as reference for genuine hunter-gatherer societies. This is an error a lot of people falls in, yet clearly confusing or misleading.

It is very possible that true Paleolithic societies had differences between them but nothing in this regard can be concluded in from studying Neolithic peoples, the same that nothing can be concluded from studying urban societies or hamsters. They are apples and oranges.

We must strictly abide to research genuine hunter-gatherer populations of which there are several examples in that part of the World, notably the various "Negritos" peoples but also the Mlabri and even the Ainu.

Much more difficult is to study Paleolithic life in West Eurasia as not a single hunter-gatherer group has survived as such over here. Probably the last Western foragers vanished thousands of years ago. But that does not make the Maori a better representative than, say, the Saami, the Bedouins or even the Parisians. Would you be talking of the Andamanese or the Bushmen, I'd take it as valid but the Maori are as good as the inhabitants of Tokyo.

"Certainly larger groups than Neanderthals seem to have been for example".

No idea where do you get your notions of Neanderthal group size. I have no reason to think that Neanderthal groups were smaller than those of our species. Their provisioning areas were somewhat more reduced but I'm not sure if one implies the other.

And disagree with all the rest as well but do not wish to be repetitive.

@terryt - I'm in the Far North. Of note, I found a very nicely crafted green greywacke adze in a crevice near a sea cave a few weeks ago. In Europe, such a thing would be upper paleolithic, here it could be less than 200 years old.

As for the paleolithic Europeans, great new paper about early British cannibals crafting skull cups calibrated to 14,700 ybp:http://www.plosone.org/article/info:doi/10.1371/journal.pone.0017026

Kenniwick man had an arrowhead in his pelvis, the Ice Man died of violence, I can't help but think of the hunter gatherer times being not unlike modern gangster culture.

Ötzi "the Ice Man" was not any hunter-gatherer. He actually lived in one of the most violent periods of post-Neolithic Europe: the Chalcolithic!

You people mix apples and oranges in a way that really sucks.

Nobody says that there was no violence among hunter-gatherers. Inuits eventually drove the Tuniit to extinction, Cheddar Man was a cannibal and there are indeed instances of violence among modern huntergatherers. But these are not "gangster culture" because gangsters have complex hierarchies that can only evolve when there's something to distribute such as grain, cattle, land or gold.

Hunter-gatherers live by the day or almost and depend too much on the good will or their fellows to degenerate into such exploitative hierarchies. Sure, now and then someone snaps and kills someone else: weapons are at hand and killing is way too easy but for that very reason they must work hard to impede society from degenerating in a violent nightmare, for that reason they have pacifist cultures (even if violence is relatively common as well). And all that without any hierarchies.

"great new paper about early British cannibals"...

They crafted human skulls but we have no particular reason to think they were "cannibals" (they were unrelated to Cheddar Man). The skulls could well be those of their non-eaten enemies or their non-eaten relatives. Many cultures recycle skulls of dear relatives as objects of symbolic value. Maybe that's the reason behind those modified skulls.

The Bello et al paper mentions processing of human mandibles to suck marrow, with the same butchery techniques used as on deer, horse, and lynx mandibles found at the same site - short of finding human coprolites with human muscle residue in them (as at an Anasazi site), I can't think of much more compelling evidence of cannibalism at Gough's Cave

"Hunter-gatherers live by the day or almost and depend too much on the good will or their fellows to degenerate into such exploitative hierarchies. Sure, now and then someone snaps and kills someone else: weapons are at hand and killing is way too easy but for that very reason they must work hard to impede society from degenerating in a violent nightmare, for that reason they have pacifist cultures (even if violence is relatively common as well)".

Only within their own tribal group. Members of other tribes are definitely discouraged from entering another tribe's foraging region.

"Why are you so opposed to the concept when so much evidence points in favour of it?"

Which one the belief in humans systematically depleting the resources of every single habitat they colonize, even in small numbers and with highly primitive technologies? Or the belief that Neolithic peoples are the same as Paleolithic peoples?

In the first case, the evidence is scant, controversial and inconclusive. So I choose not to believe in one doctrine but to leave the matter wide open and concede the "accused" the benefit of the doubt (i.e. innocent till proven guilty, right?)

In the second case, it's just plainly wrong. I flatly reject to obviate the huge differences between the socio-economies of these two so extremely different ways of life. You guys chose to do otherwise because you want to believe certain things and for that the evidence from real hunter-gatherers is inconvenient, so you chose other societies as proxy. You could well chose a Roman gladiator arena for what I care or even the ovens of Auschwitz.

"In the first case, the evidence is scant, controversial and inconclusive".

Rubbish. The evidence is overwhelming that they did so. Species with very slow reproduction rates rapidly become extinct with even just a small increase in predation. However many people are much more contented believing that somehow 'Noble Savages' lived in complete harmony with their surroundings. A romantic notion if ever there was one.

"innocent till proven guilty, right?"

Already proven guilty, I'm afraid.

"I flatly reject to obviate the huge differences between the socio-economies of these two so extremely different ways of life".

Humans are basically the same now as they've been for the last 50,000 years at least. It's just the method of survival has changed to some extent.

"the evidence from real hunter-gatherers is inconvenient"

In what way is it 'inconvenient'?

"You could well chose a Roman gladiator arena for what I care or even the ovens of Auschwitz".

"In general hunter-gatherers today and historically live in quite good harmony with their environments. That's a fact and you will be pushed hard to find a exception".

Yes. Because for long-term survival every species must adjust, and live in some sort of harmony with their environment, or the species will become extinct. But development of that harmony can take many generations, and in the meantime the environment changes to accomodate them.

"You just choose to BELIEVE in one option because of your inquisitorial attitude on the matter: 'They are witches, I know it! Mwahahaha!'"

No Maju. It is you who persist with that attitude.

"I have been posting some info in Leherensuge and here that is clearly contradictory with such a verdict".

No you haven't. The last thing I remember was a claim that fire hadn't caused the megafauna extinction in Eurasia. It didn't deny that humans may have caused the extinction, just that they didn't do it through the use of fire. And the article ignored the extreme likelihood that the forest expansion was the result, not the cause, of the megafauna extinction. Besides which I think the author of the paper on fire is the author of the following book, Chris Johnson:

He is in no doubt as to what caused the Australian mammal extinctions, both ancient and modern: people. I suggest you try to find the book at a library. But because you're so resolutely opposed to accepting the fact I presume you will make no effort to track down, let alone read, the book.

"Your memory is extremely selective. Because you have read and posted comments in all those"

Yes, of course I've read them all. Surely even you can see that for all the papers the default position is that humans caused the extinctions. The papers are merely attempts to put forward an alternative scenario. Not one of these alternatives are at all convincing.

Whatever your opinion on the matter, all those articles and papers FOUND (of course always just a qualified but subjective judgment) that there was no such systematic maladjustment as some other prehistorians, those you favor, have tried to argue for based only on very circumstantial and weak evidence, as far as I can discern.

The case is widely open and not closed as you pretend. More so, I'd dare say that the former verdict of guilt has been appealed and revoked because of the presumption of innocence and lack of evidence from the accusation.

"More so, I'd dare say that the former verdict of guilt has been appealed and revoked because of the presumption of innocence and lack of evidence from the accusation".

The arguments against a guilty verdict are convincing only to those who wish desperately to be convinced. Anyone with the slightest knowledge of ecology or population dynamics immediately sees holes in any of the arguments that you could fly a 747 through.

I'll quote from the book I mentioned earlier. I'm absolutely sure you will make no effort to read it because you are so opposed to the conclusions.

"The evidence contained in the selectivity of extinctions has been largely ignored in the extinction debate. Mostly the selectivity of extinctions has been invoked to buttress rather than test them. Typically someone will identify a single trait thought to have been shared by the extinct species (such as that, as large animals, they need to drink a lot), build an extinction scenario around that trait, and then re-emphasise the trait's significance to strengthen the original hypothesis. This style of argument ignores the many other features of species that might affect their ability to survive a given threat and that could be used in testing hypotheses, and it makes almost no use of the species that survived".

And doesn't that so much apply to the papers you have cited!

"There are three distinct ways in which it is possible to test if some factor might have been the cause of long-past extinctions. They consist of asking the following questions: Was the factor correlated with the extinctions in space and time? ... Does the factor explain why certain species went extinct and others survived? ... Could it have been powerful enough to account for the magnitude of the extinction event? ... In testing hypotheses on the megafauna extinctions I intend to work to this standard: if a hypothesis passes all three tests it may well be true, but if it is clearly inconsistent with any one test then it should be rejected".

The alternative claims for no human role in extinctions all fall down on this three-way test.

"In general, if an environmental shift was the cause of the extinctions, one would not expect species with contrasting ecological requirements to have declined in similar ways".

I'm sure you can think of examples you've quoted where that is a major weakness.

"The challenge has been to identify a convincing scenario in which hunting by a (presumably) small human population could have caused the extinction of so many species".

I'm sure you will agree with that.

"A good generalisation is that all animal species in which females produce less than one offspring per year went extinct after the arrival of people in a new land, whether they were quite small species like some marsupials and lemurs, or giants like mammoths and groud sloths. The only consistent exception to this rule are slow-reproducing survivors such as tapirs or long-beaked echidnas that live in densely vegetated habitats, or sloths and tree kangaroos that live in trees".

"Ecological theory provides the mathematical tools needed to simulate the dynamic inter-action between populations of megafaunal prey and their human predators ... A simulation using such a model typically begins with a pristine environment with megafauna at carrying capacity, introduces an initially small human population, runs the model forward until a steady state is reached, then repeats the simulation many times with different parameter values to test the robustness of the final model. Alroy (2001) modelled the impact of people on mammal megafauna in North America in this way and Holdaway & Jacomb (2000) did the same for people and moa in New Zealand, while Brook & Bowman (2004) created a more general family of models that provided results applicable to Australia. All these studies concluded that extinction of large vertebrates was a consistent, almost inevitable consequence of human arrival, because the reproductive rates and densities of these large vertebrates were low relative to the potential popualtion density of people and the predation rates they could have imposed".

And further:

"the fact that adult females produce only single offspring that do not mature until six years old means that juveniles killed by hunters are replaced very slowly, and a small increase in mortality of juveniles can hold the recruitment rate below levels needed to replace natural mortality of breeding adults".

"So the general answer to the question of how much hunting by people would have been sufficient to drive megafauna species extinct is that very low rates of killing, representing only small rates of mortality imposed on the hunted population, could have done it. The problem of the lack of archeological evidence of hunting can now be seen in a very different light... Also, because the additional mortality imposed by hunters may well have been small, the majority of indivivual animals would have died natural deaths even as their population declined to extinction as a result of overhunting".

Concluding:

"The chronological evidence supports direct human impact, not climate change or fire, as the cause of the megafauna extinctions... The evidence from the selectivity of extinctions is much clearer. The extinction pattern is the one we would have expected had overhunting been the cause... Certainly the process has been repeated many times since. Wherever humans have harvested from their environments, long-lived, slow-breeding and slow-maturing species, living in situations that guaranteed high exposure to people, have been the most likely to disappear".

"However, one universal prediction, which applied in all scenarios in which the empirical distribution was correctly predicted, was for the extinctions to be rapid following human arrival and for surviving fauna to be suppressed below their pre-‘blitzkrieg’ densities. In sum, human colonization in the late Pleistocene almost certainly triggered a ‘blitzkrieg’ of the ‘megafauna’, but the operational details remain elusive".

And this one, which is less certain about humans having the sole role. The authors suggest that human arrival along with climate change was the deciding factor. However they ignore the extreme likelihood that it was precisely that climate change that allowed humans to expand through each region it the first place. The authors are certainly at a loss as to how to explain the fact that the megafauna have survived similar climate changes many times before they became extinct.

So you're absolutely sure that all the authors of all these papers are 'guilty of gross misrepresentation of the facts'? Why am I not surprised? You have a well-established track record of not letting the evidence influence your predjudices.

@Millán: thanks for the link. I am a little oversaturated of info these days and maybe not able to grasp well what the author means but I gather that you probably liked this part:

"We need to stop looking at artifacts as expressions of evolutionary states and start looking at them as byproducts of behavioral strategies".

But I think that both views miss the poit pretty much: they often are neither 'evolutionary states' nor 'byproducts of behavioral strategies': largely they are products of culture and culture is not only objective, materialist, pragmatic, but (also, largely) subjective, affective, emotional, inertial. I think that anthropologists (and hence prehistorians) should know what is culture by now but maybe they miss the point all the time?

Subjectivity, either individual or collective is central to culture. There's absolutely no material or practical or strategical reason for a mosque or a statue, there's even no material reason for the alternative use of fingers, chopsticks or forks... for whether you prefer The Clash or Beethoven... all those are totally subjective matters that cannot be described in pragmatist terms.

But one thing culture does is to be ruled by inertia: it tends not to change too much, specially when the choices are similarly useful. So if two populations share cultural elements there is a good chance that they are also related biologically. That is specially true for the hunter-gatherer socio-economical reality.

Of course you're not only accusing Chris Johnson of ''gross misrepresentation of the facts', you're accusing all the other authors of doing so as well. Surely you can see that the reason 'climtae change' is invoked so often is that 'funding' is almost guaranteed with that phrase in the title. Just as a few years ago, during the drug companies' manipulation of the bird 'flu scare, super epidemics were invoked. No-one gains any funding by proposing that simple human population increase was responsible for any extinctions.

Please, be reasonably respectful when making comments. I do not tolerate in particular sexism, racism nor homophobia. Personal attacks, manipulation and trolling are also very much unwelcome here.The author reserves the right to delete any abusive comment.

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